Periodic Sequence Distribution of Product Ion Abundances in Electron Capture Dissociation of Amphipathic Peptides and Proteins
Periodic Sequence Distribution of Product Ion Abundances in Electron Capture Dissociation of Amphipathic Peptides and Proteins
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DOI：
10.1016/j.jasms.2009.02.015
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发表时间：
2009-06-01
影响因子：
3.2
通讯作者：
Tsybin, Yury O.
中科院分区：
文献类型：
--
作者：
Ben Hamidane, Hisham;He, Huan;Tsybin, Yury O.
肽和蛋白质的电子捕获解离 (ECD) 质谱分析中产物离子形成的规则仍不清楚。随机主链裂解概率和 ECD 对氨基酸序列的非特异性已有报道，这与基于缓慢加热的串联质谱法中的优先断裂通道相反。在这里，我们证明，对于两亲性肽和蛋白质，沿序列的 ECD 产物离子丰度 (PIA) 的调节是显着的。此外，由于两亲性肽的特定一级（大概是二级）结构，ECD 中的 PIA 表现出清晰且可重复的周期性序列分布。一方面，ECD PIA 的周期对应于肽一级序列内空间分离的疏水性和亲水性结构域的周期性分布。另一方面，同一周期与二级结构单元相关，例如以溶液相结构而闻名的α-螺旋圈。基于大量例子，我们制定了两亲性肽和蛋白质的 ECD 的一组特征：（1）观察到 PIA 的周期性分布，并且在广泛的 ECD 参数和不同的实验平台上可重复； (2) PIA的局部极大值不一定位于带电点附近； (3) ECD之前的离子激活不仅扩大了产物离子序列覆盖范围，而且保留了离子产率调节； (4) 最有效的裂解（例如 ECD PIA 分布的全局最大值）可以远离带电位点； (5) PIA最大值的数量和位置与氨基酸疏水性最大值相关，通常在单个氨基酸置换内； (6)优先切割位点遵循α-螺旋肽片段中选定的氢脊柱。目前提出的关于 ECD 行为的新见解对于增进对 ECD 机制的理解非常重要，特别是肽序列对 PIA 的作用。改进的 ECD 模型可以促进蛋白质测序并改善蛋白质组学技术中未知蛋白质的识别。在结构生物学中，α-螺旋结构的 ECD 中的周期性/优先产物离子产量可能为气相中肽和蛋白质的从头位点特异性二级结构测定及其与溶液相结构的相关性开辟了道路。 (J Am Soc Mass Spectrom 2009, 20, 1182-1192) (C) 2009 由 Elsevier Inc. 代表美国质谱学会出版
The rules for product ion formation in electron capture dissociation (ECD) mass spectrometry of peptides and proteins remain unclear. Random backbone cleavage probability and the nonspecific nature of ECD toward amino acid sequence have been reported, contrary to preferential channels of fragmentation in slow heating-based tandem mass spectrometry. Here we demonstrate that for amphipathic peptides and proteins, modulation of ECD product ion abundance (PIA) along the sequence is pronounced. Moreover, because of the specific primary (and presumably secondary) structure of amphipathic peptides, PIA in ECD demonstrates a clear and reproducible periodic sequence distribution. On the one hand, the period of ECD PIA corresponds to periodic distribution of spatially separated hydrophobic and hydrophilic domains within the peptide primary sequence. On the other hand, the same period correlates with secondary structure units, such as a-helical turns, known for solution-phase structure. Based on a number of examples, we formulate a set of characteristic features for ECD of amphipathic peptides and proteins: (1) periodic distribution of PIA is observed and is reproducible in a wide range of ECD parameters and on different experimental platforms; (2) local maxima of PIA are not necessarily located near the charged site; (3) ion activation before ECD not only extends product ion sequence coverage but also preserves ion yield modulation; (4) the most efficient cleavage (e.g. global maximum of ECD PIA distribution) can be remote from the charged site; (5) the number and location of PIA maxima correlate with amino acid hydrophobicity maxima generally to within a single amino acid displacement; and (6) preferential cleavage sites follow a selected hydrogen spine in an a-helical peptide segment. Presently proposed novel insights into ECD behavior are important for advancing understanding of the ECD mechanism, particularly the role of peptide sequence on PIA. An improved ECD model could facilitate protein sequencing and improve identification of unknown proteins in proteomics technologies. In structural biology, the periodic/preferential product ion yield in ECD of a-helical structures potentially opens the way toward de novo site-specific secondary structure determination of peptides and proteins in the gas phase and its correlation with solution-phase structure. (J Am Soc Mass Spectrom 2009, 20, 1182-1192) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry